1. Field of the Invention
This invention relates generally to standing valves and, more particularly, but not by way of limitation, to standing valves which facilitate the equalization of pressures above and below the standing valve.
2. Description of the Prior Art
Prior art standing valves have in general been excessively long, thereby precluding the use thereof in rough or kinky grades of tubing. Further, the packing elements employed in the prior art standing valves usually provide less than a satisfactory seal when used in a badly pitted or scored tubing string, thereby requiring the use of a plurality of such packing elements on each standing valve. In addition, prior art equalizing standing valves have in general had the fishing neck formed as an integral part of the valve stem, thereby subjecting the valve and valve seat to excessive stresses when the standing valve is set by jarring down on the fishing neck.